The
http://www.metmuseum.org/toah/works-of-art/1979.356">Heilbrunn Timeline has a very valid, I think, discussion of this work.
Identified with the Belgian Surrealist movement, although never an official member, Paul Delvaux was influenced by his contemporary René Magritte, as well as by the Italian Metaphysical and proto-Surrealist painter Giorgio de Chirico. Like Magritte, Delvaux relied on the provocative and incongruous juxtapositioning of precisely rendered objects, persons, or situations to create imaginative dreamscapes. From de Chirico he adopted the use of dramatic settings characterized by receding diagonals and classical architecture. With a sense of theater, he evokes a classical world that, in fact, never existed. Here, the architectural elements are reminiscent of Greek temples—like those on the Acropolis—and secular Roman architecture, but do not represent any known buildings. In assimilating a variety of images, Delvaux's goal was to produce "poetic shock" by "putting heterogeneous but real things together in an unexpected way." Yet, despite these strong Surrealist associations, Delvaux saw himself as following in the realist tradition of older Flemish artists like Jan van Eyck and Hans Memling.
Unique to Delvaux's compositions are the somnambulant women that recur obsessively in his work. Unabashedly unselfconscious in their dishabille (which enhances their erotic presence), they are formidable, even threatening, in their quiet seduction. In the far distance of this painting, a lone man in a bowler hat (à la Magritte) seems mesmerized by a group of beached mermaids. Although the exact meaning of this allegory remains ambiguous, it seems to touch on such enduring themes as love and erotic fantasy. Measuring over six feet by nine feet, The Great Sirens is one of the largest paintings ever executed by the artist.
Source: Paul Delvaux: The Great Sirens (1979.356) | Heilbrunn Timeline of Art History | The Metropolitan Museum of Art
I actually have more affection for Delvaux than for Magritte, although Magritte was a great artist.
My favorite painting by Delvaux is the first one I ever saw, albeit only in reproduction,
Phases of the Moon II, which I will post at some future date. Nothing ever said to me more about missing the sheer beauty of existence by getting lost in abstractions.